JPH04215767A - Expansion catheter and guide wire - Google Patents

Abstract

PURPOSE: To provide a balloon expansion catheter system having the advantage of the flat outer shape of a fixed wire system allowing the replacement of a catheter without changing the position of the guide wire. CONSTITUTION: A system 10 is provided with a catheter and a guide wire 20 capable of being locked together to be operated by the same method as an integrated catheter. When the lock is released, the guide wire 20 can be independently operated by the same method as an over-the-wire catheter system. In the latter operation mode, the length of the guide wire at the base end is extended, and the catheter can be extracted from a patient without changing the position of the guide wire 20. The succeeding catheter can be advanced to the position of the blood vessel to be treated along the guide wire 20 while the position of the guide wire 20 is kept stationary.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD This invention relates to subcutaneous transluminal angioplasty and to a flat balloon catheter and guidewire system that allows catheter exchange while the guidewire remains in a selected location.

0002

2. Description of the Related Art In recent years, subcutaneous transluminal angioplasty has become a common method for treating occlusions (stenotic sites) in arteries. The most common type of treatment uses a balloon dilation catheter, which is advanced through the patient's artery to the stenosis and then dilated with pressure to widen the stenosis. Such dilation results in improved blood flow and circulation in the treated artery. When angioplasty is applied to the coronary arteries, the method is commonly referred to as subcutaneous transluminal coronary angioplasty (PTCA). PTCA is a less complicated procedure than coronary artery bypass surgery. The PTCA procedure is relatively quick and requires a PTCA balloon dilation catheter to puncture the skin and artery (usually the femoral artery in the patient's leg) to access the patient's artery. . The PTCA catheter is manipulated with the aid of a guide wire and guided through the patient's artery to the stenosis site in the coronary artery. The balloon portion of the catheter is advanced to the stenosis and then expanded to enlarge the lumen of the artery through the stenosis.

PTC, called the over-the-wire method
One method of guiding an A catheter to a stenosis site is disclosed in US Pat. No. 4,545,390 to Leary, which is incorporated herein by reference. The method uses a thin flexible guidewire that is advanced within the patient's vasculature until its tip is in the desired location. The direction of guidewire advancement is controlled by the physician by monitoring the position of the guidewire using fluoroscopy. Once the guidewire is advanced to the desired location, a balloon dilatation catheter is advanced over the guidewire and the guidewire is received within the guidewire lumen that extends through the catheter. In this way, the guidewire dilation catheter is easily and automatically guided directly to the desired site.

0004

Some occlusions are extremely difficult to access or expand due to their location or geometry. More specifically, the stenosis site may be located within or beyond a highly tortuous artery and thus may be extremely difficult to reach. In other cases, the stenosis may occlude most of the artery, leaving only a very narrow opening across which it is extremely difficult to properly position the balloon portion of the dilation catheter. There are also more complex cases where these two conditions are combined.

[0005] In general, stenosis sites with narrower openings require the use of balloon catheters having a correspondingly smaller deflated cross-section, a property referred to as a flatter profile. In the over-the-wire systems described above, the deflated balloon shape was reduced by reducing the outer diameter of the catheter shaft and the inner diameter of its guidewire lumen in the region of the balloon. Because of this reduced diameter, the balloon will have a very small outer diameter when deflated and folded around the catheter body. However, in over-the-wire systems, there is a minimum limit to reducing the guidewire inner diameter because the physician must thread the catheter over the guidewire and withdraw the guidewire through the guidewire lumen. Thus, the guidewire lumen must always be wide enough to allow complete penetration of the guidewire. A typical over-the-wire catheter has an off-axis diameter on the order of 0.050 inches.

[0006] Apart from this, an integral (non-removable)
Dilatation catheters with guidewires have been developed. Such catheters are also referred to as "wire-fixed" catheters. Examples of such fixed guidewire catheters are U.S. Pat.
No. 70, No. 4,641,654 and No. 4,554,9
It is described in No. 29. In these systems, the guidewire is an integral part of the catheter and cannot be separated from the catheter shaft. This allows the use of a flattened catheter since there is no need to provide a guidewire lumen wide enough to allow the guidewire to pass through.

However, the inability to separate the guidewire from the catheter within a fixed wire catheter creates several problems as the catheter cannot be exchanged with another catheter over the guidewire. . Interchangeability of the catheter is desirable in that it allows the physician to change balloon dimensions as needed for many reasons and purposes. Typically, for over-the-wire catheters, catheter exchange involves attaching an extension wire to the proximal end of the guide wire, removing the indwelling catheter from the patient over the extended guide wire, and then extending a new catheter. This is done by sliding the guidewire along the guidewire to the stenosis site. The guidewire extension can then be removed from the guidewire. Such a method is described in US patent application Ser. No. 07/206,008, filed June 13, 1988. In contrast, when using a fixed guidewire catheter, the catheter and guidewire are naturally removed together as a unit. Subsequent catheter positioning requires the insertion of a new guidewire or catheter with an integral guidewire into the patient's artery and back to the stenosis site, and thus the time required for this method. and increased risk to the patient.

[0008]Therefore, there is a need for a catheter that has the advantages of the flattened shape of a fixed guidewire catheter, but which allows for catheter exchange without loss of guidewire position. It is an object of the present invention to provide such a catheter mechanism.

[0009]

SUMMARY OF THE INVENTION The present invention has a flattened configuration and the handling features of a fixed guidewire catheter, but provides a flattened multi-catheter catheter that has the flattened shape and handling features of a fixed guidewire catheter, but which allows catheter exchange over an extensible guidewire. It is an object of the present invention to provide a catheter system that employs a combination of lumen dilation catheters. The system includes a steerable guidewire having an elongated flexible shaft and a highly flexible tip portion, preferably in the form of a helical coil attached to the end of the shaft. The guidewire region to be placed within the balloon portion of the catheter is reduced in diameter. The catheter includes a flexible elongate shaft and an expansion balloon attached to the end of the shaft. The expansion lumen and guidewire lumen are
Extending through the catheter shaft, the expansion lumen communicates with the inside of the balloon to inflate and deflate the balloon, and the guidewire lumen extends completely to and terminates in an exit at the distal end of the shaft. ing.

[0010] To provide a mechanism with a flatter outer diameter within the balloon region, the catheter shaft extending through the balloon region is reduced in diameter as permitted by the reduced diameter of the guidewire in that section. This is because the guide wire lumen of the catheter shaft is also reduced in diameter. No portion of the passageway defined by the guidewire lumen has a diameter smaller than the maximum diameter of the guidewire shaft. The diameter of the distal portion of the catheter shaft is comparable to the diameter of the distal helical coil of the guidewire and cannot be removed through the guidewire catheter lumen. However, the catheter can be withdrawn relative to the guidewire while the guidewire remains stationary. For this purpose, the proximal end of the guide wire is
Connector means are provided by which the elongate wire can be attached to the proximal end of the guide wire. The elongated wire exposes a portion of the guidewire, or an extension thereof, when the catheter is withdrawn proximally over the guidewire and the extension thereof;
Allow the doctor or assistant to grasp it. next,
The catheter can be replaced with another catheter as required by the physician. In order to facilitate handling of the guide wire and catheter as a unit in the fixed wire catheter method, a locking mechanism is provided at the proximal end of the catheter, and the locking mechanism secures the proximal end of the guide wire to the proximal end of the catheter. These are firmly locked together so that they can be operated and advanced together.

In one mode of operation, the catheter and guidewire are locked together at their proximal ends and both can be manipulated and steered together. When operated in this manner, the catheter system functions as a fixed wire dilatation catheter. In the second mode of operation, the catheter and guidewire are not locked together and can be operated independently of the guidewire catheter. In this second mode of operation,
The guidewire is extended at its proximal end and the catheter can be exchanged for another catheter while maintaining the guidewire distal position within the stenosis.

[0012] The system provides a catheter with contours and handling characteristics similar to fixed guidewires, and provides a catheter that can be withdrawn and replaced without losing the guidewire's position within the artery. do. In this way, there is no need to advance a new guidewire to the stenosis site again.

One of the general objects of the present invention is to provide a balloon dilatation catheter system that has the advantage of a flat profile of a fixed wire system that allows catheter exchange without losing guidewire position. It is.

Another object of the invention is to provide a catheter system comprising a balloon dilatation catheter and a steerable guide wire, the guide wire being operable independently of the catheter or as a unit with the catheter. It is.

Still another object of the present invention is to provide a catheter and guidewire system of the type in which the proximal end of the catheter includes means for removably locking the guidewire to the proximal end of the catheter.

[0016]

The above and other objects and advantages of the present invention will be apparent from the following detailed description read in conjunction with the accompanying drawings.
be better understood.

Referring to FIG. 1, the dilation catheter/guidewire system 10 of the present invention includes an elongated flexible catheter shaft 12 formed of any of a number of suitable polymeric materials commonly used in such catheters. It is equipped with The catheter shaft 12 has a guidewire lumen 14 adapted to receive a guidewire 20 and at least one dilatation lumen 16. The catheter can be as long as 135 cm. The diameter of shaft 12 can be comparable to the diameter of a fixed guidewire catheter of approximately 0.030 inches. A dilatation balloon 18 is attached to the tip of the catheter and communicates with the dilatation lumen. The balloon can be formed as described in US Pat. No. 4,490,421 to Levy.

A molded Y-fitting 17 is integrally attached to the proximal end of the shaft 12 to form an internal connection between the lumens 14, 16 and the pair of flexible proximal tubes 19, 21. do the work. The proximal tubes 19 and 21 each have an expanded lumen 16
and communicates with guidewire lumen 14 . Tube 19 terminates in a standard Luer connection 22. The proximal end of tube 21 has a rotatably sealable attached adapter assembly 23.
have. The adapter assembly 23 includes a Y-fitting 24 fixed to the proximal end of the tube 21 and a Tuohiborst (Tu) fitting attached to the Y-fitting 24 at a rotary joint 50.
A rotatable locking element 26 such as an ohy-Borst adapter can be provided. O-ring 52
forms a dynamic rotary seal between locking element 26 and Y-connection 24, thereby locking element 26
Allows rotation without leakage. Adapter assembly 23 communicates with guidewire lumen 14 of catheter shaft 12 through tube 21 and has a lumen 54 through which the guidewire can pass. Side arm 56
is provided in the Y-connector 24, and the inner lumen 5 of the adapter
4, thus allowing fluid communication with the guidewire lumen 16. Rotatable locking element 26 includes an end cap 58 threaded into body portion 60 by screw 62;
The end cap 58 includes a compressible bushing 27. Although the bushing 27 can be made of a variety of elastic compressible materials, silicone elastomer is preferably used.

In use, guidewire 20 extends through lumen 54 of adapter 23. When end cap 58 is loosened, compressible bushing 27 relaxes into its expanded configuration. In this configuration, the unit is unlocked and the guide wire can be rotated and moved axially relative to the catheter. However, when end cap 58 is tightened, it compresses bushing 27. Due to the force acting on the compressible bushing 27,
The bushing 27 is compressed about a guidewire extending through the bushing 27. In this way, the guidewire is sealed and locked to the catheter. This engagement prevents axial movement of the guidewire. When locked to the catheter in this manner, the guidewire can be rotated by the locking element 26. The ability to rotate the guidewire allows it to be steered to a selected location within a patient's blood vessel even when locked to the catheter. When locked together, catheter 12 and guidewire 20 can be manipulated together in a manner similar to a catheter with an integral fixed guidewire. Once unlocked, guidewire 20 can be rotated independently of the catheter and advanced.

As shown more clearly in FIG. 2, the extensible and steerable guidewire 20 is made of stainless steel and has a tapered distal end 29 and a distal end 28 attached to its distal end. It has a shaft 30 that can be formed. The tip portion 28 may include a helical coil 32 secured to the tip of the core wire by suitable means such as a solder joint 34. A tip weld 36 is secured to the leading edge of the coil and provides a rounded end to the guidewire to prevent injury to the patient when advancing and manipulating the guidewire. Coil 32 and tip weld 36 can be made of any of a variety of materials known in the art, including radiopaque materials such as platinum and gold, as described in the above-mentioned patents. Materials are preferred.

In a preferred embodiment, guidewire tip portion 28 has a diameter in the range of about 0.016 inches to about 0.017 inches and can be on the order of 1 to 2 inches long. The shaft 30 can have a diameter on the order of 0.012 inches at its untapered distal end and extend along most of the length of the catheter. The tapered portion 29 of the guidewire 30 is about 4 to 7 mm.
It can be extended over a length of cm and tapered to a diameter of about 0.004 inch to 0.006 inch. A narrow orthopedic or safety ribbon 31 with a cross section of approximately 0.001 inches by 0.003 inches may extend from the end of the guidewire 30 to the tip weld 36.

The most proximal end of guidewire shaft 30 is illustrated in FIG. At the proximal end of the shaft 30 is a tubular socket 35 adapted to receive a guide wire extension wire.
A cylindrical portion 33 can be provided which engages and is firmly attached to the socket 35. The socket 35
The tip of is indicated schematically at 37. Connection part 33
, Socket 35 and Suitable Guidewire Extension System, June 1988, hereby incorporated by reference in its entirety.
No. 07/206,008, filed May 13th. As mentioned above, the guidewire extension system allows catheter exchange while maintaining the position of the guidewire tip within the stenosis site.

Catheter 12 can be a coaxial or extruded multi-lumen structure, or a combination thereof;
Preferably, it is made of a flexible polymeric material such as polyethylene. In the embodiment shown in FIGS. 1 and 2, the catheter includes a multi-lumen shaft 12 having a catheter tip section 48 secured at a tip fitting 44. In the embodiment shown in FIGS. Catheter tip 48 is formed of polyimide and can be connected to the catheter shaft by various methods known in the art, such as heat sealing or adhesives. Alternatively, catheter shaft 12 and catheter tip 48 can be of single piece construction, with tip 48 thermoformed and formed onto the distal end of catheter shaft 12 during manufacturing of the shaft. Catheter tip 48 defines an extension of guidewire lumen 14 and terminates in tip exit orifice 25 . If the catheter shaft 12 and catheter tip 48 are formed as separate members, the tip of the catheter shaft is constricted during assembly in the region of the guidewire lumen 14;
It is desirable that it smoothly merge with the proximal end of the distal end 48. This downward constriction can be achieved by heat and pressure molding. Catheter tip 48 is on the order of twelve inches long and has a diameter substantially smaller than the more proximal portion of shaft 12, which has an outer diameter on the order of 0.014 to 0.016 inches. The small diameter of the distal end of the catheter shaft facilitates deflation of the balloon 18 into a highly flattened configuration. Correspondingly, the inner diameter of guidewire lumen 14 exiting the tip at tip exit orifice 25 is extremely small, 0.012 to 0.014 inches.

The expansion lumen 16 terminates proximally of the catheter tip 48 and communicates with the interior of the expansion balloon 18 . Balloon 18 can be made of various polymeric materials, but polyethylene terephthalate (PET) is preferably used. Balloon 18 can be adhered to the catheter shaft at its end with a suitable adhesive such as cyanoacrylate. At least one radiopaque marker band 46 can be formed on the distal end portion 38 of the catheter below the balloon so that the position of the balloon can be visually verified by fluoroscopy during use. . A radiopaque marker (not shown) can also be placed on the catheter shaft proximal to the balloon.

Guidewire lumen 1 at the tip of the catheter
The inner diameter of 4 is large enough to receive and advance the guidewire shaft 30 until it reaches the guidewire tip portion 28. In a preferred embodiment,
The inner diameter of the guide wire lumen 14 at its tip is approximately 0.0
12 to about 0.014 inches. Catheter tip 48 in the illustrated embodiment is similar to guidewire tip 28.
It will be understood that the inner diameter is smaller than the outer diameter of. Therefore, it is possible to use a smaller outer diameter catheter tip 48 that is approximately equal to the outer diameter of the guidewire tip 28. Such a design does not allow guidewire 20 to be withdrawn from the catheter because the guidewire tip cannot pass through tip exit orifice 25, but allows guidewire tip 28 and catheter tip 48 to be removed at the distal end of the device.
This has the advantage of providing a relatively smooth transition between. Such a configuration is desirable because there are no discontinuities along the length of the catheter shaft that would impede movement of the catheter.

Using adapter assembly 23, guidewire 20 can be sealed to the catheter in a manner that allows rotation of the guidewire while preventing axial movement of the guidewire relative to the catheter. Can be locked. Thus, in the locked configuration, the catheter and guidewire can be axially advanced or withdrawn as a single unit in the same manner as a conventional flat fixed unitary wire catheter. I can do it. The guidewire can rotate while locked to the catheter, allowing the locked unit to be steered to a desired position within the patient's blood vessel. Alternatively, the adapter 23 can be loosened, allowing the physician to advance the guidewire independently of the catheter. Thus, when the guidewire is locked to the catheter, the system can be operated in a manner similar to a catheter with an integral guidewire, and when the guidewire is unlocked from the catheter, the system can be operated like an over-the-wire catheter. /Can be operated in the same manner as a guide wire system. The present system is not intended to be limited to catheters of dual lumen construction. Coaxial catheters and catheters with three or more lumens are also applicable. For example, FIG. 4 is an axial cross-sectional view of a catheter having three lumens in the distal region of the expansion lumen. The shaft 61 has a guidewire lumen 62 and two expansion lumens 64, 6.
6. Guidewire 20 is positioned within the guidewire lumen. The expansion lumens 64, 66 are symmetrical and have a minimum inner diameter of approximately 0.010 inches. The guidewire lumen is circular and has an inner diameter of approximately 0.016 inches in the region proximal to the balloon. The guidewire has a cross-sectional outside diameter of approximately 0.010 inches.

The dilation catheter/guidewire system described herein combines the advantages of over-the-wire and fixed unitary guidewire systems. As in fixed guidewire systems,
The system has a very flat profile, with a catheter shaft on the order of 0.030 inches in diameter, making it easy for physicians to manipulate. However, unlike fixed guidewire systems, this system overcomes the drawback of not being able to exchange catheters without displacing the guidewire. The catheter can be withdrawn from the patient without disturbing the position of the guidewire. The system also allows the guidewire to receive an extension 37 at its proximal end to permit catheter exchange as described in more detail in the above-referenced patent application Ser. No. 07/206,008. The system also sealably locks the guidewire and catheter together, allowing operation as a single unit while allowing independent movement of the guidewire and excellent steering.

The guidewire/catheter system described herein can be advanced through a prepositioned guide catheter into a coronary artery, as is well known and common practice.

Once the guide wire and dilation catheter have been advanced through the guide wire into the coronary artery and the balloon is positioned within the occlusion, its location should be confirmed fluoroscopically with a radiopaque marker. I can do it. Injecting radiopaque contrast fluid through the guide catheter allows visual confirmation of the anatomy. Additionally, in one mode of operation, termed "half-exchange," maximum flow of contrast fluid can be achieved while maintaining the selected position of the guidewire. In this mode of operation, the guidewire is extended with the extension wire 37 and a portion of the catheter is withdrawn from the patient over the guidewire extension 37. A radiopaque contrast fluid is then injected through the guide catheter while the guidewire remains in place. This method allows maximum dilation to be achieved while maintaining the previously established position of the guidewire within the vessel.

Furthermore, the flat shape of the balloon makes it possible to inject a sufficient amount of contrast fluid along the balloon catheter while the balloon catheter is positioned within the guide catheter. Because the balloon portion is not pulled through the device at the proximal end of the guide catheter, the potential for balloon damage is minimized.

The dimensions stated here are in particular 3 French (
It should be noted that it is applicable to dilation catheters measuring 0.039 inch). These dimensions are chosen for illustrative purposes only and are not intended as limiting values. Although the present invention is applicable to catheters of a wide range of sizes, it is particularly suited for applications where a flat profile design is required. Furthermore, the specific materials are not intended in a limiting sense. Unless otherwise specified, catheters, balloons, guidewires, and related devices may be constructed of any materials commonly used in the art.

[0032] Thus, from the above explanation, the present invention
It will be appreciated that it provides the advantages of over-the-wire and fixed unitary wire catheter systems without the disadvantages of each. The present invention provides a catheter system that functions in one mode as a flattened catheter capable of steering and passing through narrow stenoses allowing catheter exchange without displacing the guidewire. . Furthermore, these advantages are realized with a system that allows independent manipulation of the guidewire and allows injection of contrast agent through the catheter.

It will be appreciated, however, that the above description of the invention is merely one example of the invention, and that other modifications and embodiments will be apparent to those skilled in the art without departing from the spirit of the invention. Should.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of the balloon dilatation catheter and guidewire system of the present invention.

FIG. 2 is an enlarged partial cross-sectional view of the distal end portion of the balloon dilatation catheter and guidewire system shown in FIG. 1;

FIG. 3 is a partial cross-sectional view of the proximal end of the guide wire showing a portion of the connector mechanism for attaching the elongated wire.

FIG. 4 is an axial cross-sectional view of one embodiment of the dilatation catheter and guidewire system of the present invention.

[Explanation of symbols]

10 Guide wire system 12 Catheter shaft 14 Guide wire lumen 16 Expansion lumen 17 Y-attachment 18 Expansion balloon 19 Proximal tube 20 Guide wire 21 Proximal tube 22 Luer connection part 23 Adapter assembly 24 Y-connection fitting 25 Orifice 26 Locking element 27 Bush 28 Tip part 29 Tip part 30 Guide wire shaft 32 Helical coil 33 Cylindrical part 34 Solder joint 35 Tubular socket 36 Tip welding part 37 Extension part 48 Catheter tip 50 Rotating joint 52 O-ring 54 Lumen 56 Side arm 58 End cap 60 Main body part 61 axis 62 screw 64 Lumen 66 Lumen

Claims (20)

[Claims] 1. A dilatation catheter and guidewire comprising: an elongated flexible catheter shaft having a proximal end, a distal end, a guidewire lumen, and a dilatation lumen, the dilatation lumen communicating with the interior of a balloon; a dilatation balloon attached to the distal end of the shaft in such a manner that the guidewire shaft extends through the guidewire lumen, a guidewire extending completely through the guidewire lumen; a flexible distal end portion fixed to a distal end thereof, the flexible distal end portion extending distally beyond the distal end of the catheter shaft; and an elongated wire at the proximal end of the guidewire. a means for attaching the guidewire, a means for removably locking the proximal portion of the guidewire to the proximal portion of the catheter, and a flexible distal portion having an outer diameter greater than the outer diameter of any portion of the guidewire shaft proximal to the catheter; a guidewire lumen of a diameter and, when locked, permitting the guidewire to rotate relative to the catheter while preventing relative axial movement between the guidewire and the catheter; A dilation catheter and guidewire comprising a locking stop means which, when unlocked, allows the guidewire to rotate and advance independently of the catheter. 2. A dilation catheter and guide wire according to claim 1, characterized in that the guide wire axis has a reduced diameter in the region of the balloon. 3. The dilation catheter and guide wire according to claim 1, wherein the inner diameter of the guide wire lumen at the distal end is smaller than the inner diameter of the guide wire lumen at the proximal end. 4. The dilation catheter and guide wire according to claim 1, wherein the outer diameter of the tip of the catheter shaft is approximately equal to the outer diameter of the tip of the guide wire. 5. The dilation catheter and guide wire according to claim 4, wherein the dilation catheter comprises a flat balloon dilation catheter. 6. The dilation catheter and guide wire of claim 5, wherein the balloon comprises polyethylene terephthalate. 7. The dilation catheter and guidewire of claim 1, wherein the guidewire includes a stainless steel shaft having a flexible tip portion at its distal end. 8. The dilation catheter and guide wire of claim 7, wherein the flexible distal end portion of the guide wire includes a helical coil. 9. The dilation catheter and guide wire according to claim 1, wherein the outer diameter of the flexible tip portion of the guide wire is larger than the diameter of the guide wire lumen at the distal end of the catheter. and guide wire. 10. The dilation catheter and guide wire according to claim 1, characterized in that the catheter body comprises a catheter body having a catheter tip portion fixed to the tip of the catheter shaft. 11. The dilation catheter and guide wire of claim 1, wherein the catheter shaft comprises polyethylene. 12. The dilation catheter and guidewire of claim 1, comprising a guidewire lumen through which a locking stop means passes, a catheter mounting portion, a body portion carrying a compressible bushing, and an end cap. A dilation catheter and guide wire, wherein the main body portion and the catheter attachment portion are connected by a rotating dynamic seal. 13. The dilation catheter and guidewire of claim 12, wherein said compressible bushing comprises a silicone elastomer. 14. A flat dilatation catheter and guidewire, an elongated flexible catheter shaft having a proximal end, a distal end, a guidewire lumen, and a dilatation lumen;
an expansion balloon attached to the distal end of the shaft with the expansion lumen in communication with the interior of the balloon; and a guidewire extending through the guidewire lumen so that the expansion balloon can extend completely through the guidewire lumen. Approximately 0.012
a shaft having a maximum cross-sectional diameter of about 0.016 inches to about 0.01 inches and fixed to the distal end of the guidewire shaft and extending distally beyond the distal end of the catheter shaft;
the guidewire having a flexible distal end portion having a cross-sectional outside diameter of 7 inches; means for attaching the elongated wire to the proximal end of the guidewire; and a means for attaching the proximal end portion of the guidewire to the proximal end portion of the catheter. means for locking; a guidewire lumen having a minimum cross-sectional outer diameter of about 0.014 inches to about 0.016 inches; and a means for allowing the guidewire to rotate relative to the catheter when locked; a locking stop means that prevents relative axial movement between the guidewire and the catheter, while permitting the guidewire to rotate and advance independently of the catheter when unlocked; A flat dilatation catheter and a guide wire. 15. The flat dilation catheter and guide wire of claim 14, wherein the balloon comprises polyethylene terephthalate. 16. The flat dilation catheter and guide wire of claim 15, wherein the catheter shaft comprises polyethylene. 17. The flat dilation catheter and guide wire according to claim 15, wherein the inner diameter of the guide wire lumen at the distal end is smaller than the inner diameter of the guide wire lumen at the proximal end. wire. 18. The flat dilatation catheter and guidewire of claim 15, comprising a guidewire lumen through which said locking stop means passes, a catheter mounting portion, and a body portion carrying a compressible bushing. an end cap, wherein the body portion and the catheter attachment portion are connected by a rotating dynamic seal. 19. The flat dilation catheter and guide wire of claim 18, wherein said compressible bushing comprises a silicone elastomer. 20. The flat dilation catheter and guide wire according to claim 15, characterized in that the catheter shaft comprises a catheter body having a catheter tip portion fixed to the tip thereof.